An inkjet printer for forming an image on a medium (recording medium) by using an ultraviolet curable color ink (color ink) for forming (printing) a color image and an ultraviolet curable ink with translucency (clear ink) for glossing the color image is generally known. (For example, Japanese Unexamined Patent Application Publication No. 2008-229945). An ultraviolet curable ink has a property of becoming hardened when being exposed to ultraviolet. Before becoming hardened, the ink may collect dust and the like. Therefore, in order to inhibit such collection or adhesion of dust, conventionally ultraviolet is irradiated to an ultraviolet curable ink landed on a medium (recording medium) at the same time as or immediately after the ink is discharged.
An ultraviolet curable ink is discharged as an ink drop from an inkjet head, and therefore the ultraviolet curable ink landed on a medium has an uneven surface. In the meantime, in the case of a conventional inkjet printer as described above, the ultraviolet curable ink is hardened immediately after it has landed on the medium. Therefore, unfortunately the ultraviolet curable ink is not sufficiently smoothened (through leveling) so that an unleveled surface becomes noticeable in a coated film formed by a hardened substance of the ultraviolet curable ink to result in a poor appearance.
Meanwhile, for the purpose of leveling the ultraviolet curable ink, it is also conceived to employ an inkjet printer in which positions of an inkjet head and an ultraviolet irradiation unit installed in a carriage are displaced from each other in a transfer direction of a medium. In such an inkjet printer, at first the carriage reciprocates in a scanning direction and discharges an ultraviolet curable ink. After the reciprocating motion of the carriage finishes, the medium is transferred in a feed direction perpendicular to the scanning direction. Then, after the transfer motion of the medium finishes, the carriage reciprocates again in the scanning direction in order to irradiate the ultraviolet curable ink, discharged onto the medium, with ultraviolet. Through these operation steps, however, dust and the like adhere to the ultraviolet curable ink yet to be cured or hardened at the time of transferring the medium. Therefore, the above-described problem that the conventional technology has cannot be solved.